In recent years, an LSI capable of processing image signals at a high speed has been requested as television sets and video cassette recorders have been digitalized and enhanced in resolution and definition. The LSI is packaged into a system LSI together with a CPU core, a memory controller, an interface, and the like, which is mounted in various kinds of electronic equipment.
A CPU core is supplied with electric power via a source line from an external AC power source through an AC-DC converter and a DC-DC converter. For example, in a case where CPU has a processing speed of 300 MHz, CPU repeats turning on/off (ON/OFF) once every about 30 ns. However, at the time of switching of CPU from OFF to ON, the voltage of CPU cannot be recovered sufficiently only by an electric current from the source line in an instant. As a result, the processing speed of CPU lowers substantially. On that account, a capacitor is connected in parallel with the source line in order to make up for an instantaneous shortage of electric current to CPU and promote prompt recovery of the CPU voltage.
As for such capacitor, a large capacitance and transient responsibility, i.e. low ESL performance, are required primarily. Also, it is required to slim the capacitor with downsizing of electronic equipments in recent years. Therefore, a mounting board with such a capacitor mounted in this way is required to be slimmed, too. To meet the requirement, a method of embedding a capacitor as a surface-mounted part in a mounting board is proposed. Such method is disclosed by Japanese Patent Unexamined Publication No. 2003-197849, for example.
However, the method of embedding a capacitor in a mounting board needs a space to embed the capacitor in. Accordingly, slimming down of a mounting board is insufficient.